package conn

import (
	"fmt"
	"io"
	"net"
	"time"

	lgbl "github.com/ipfs/go-libp2p/loggables"
	ic "github.com/ipfs/go-libp2p/p2p/crypto"
	peer "github.com/ipfs/go-libp2p/p2p/peer"
	manet "gx/QmNT7d1e4Xcp3KcsvxyzUHVtqrR43uypoxLLzdKj6YZga2/go-multiaddr-net"
	u "gx/QmQA79FfVsUnGkH3TgKDqcDkupfjqLSJ6EYwDuDDZK8nhD/go-ipfs-util"
	ma "gx/QmVUi2ncqnU48zsPgR1rQosDGwY3SSZ1Ndp33j33YjXdsj/go-multiaddr"
	mpool "gx/QmXMkWRYvXJ2NTzHMEz5794997kNPGsVX8EhFiXXpoKDZr/go-msgio/mpool"
	context "gx/QmacZi9WygGK7Me8mH53pypyscHzU386aUZXpr28GZgUct/context"
	logging "gx/QmfZZB1aVXWA4kaR5R4e9NifERT366TTCSagkfhmAbYLsu/go-log"
)

var log = logging.Logger("conn")

// ReleaseBuffer puts the given byte array back into the buffer pool,
// first verifying that it is the correct size
func ReleaseBuffer(b []byte) {
	log.Debugf("Releasing buffer! (cap,size = %d, %d)", cap(b), len(b))
	mpool.ByteSlicePool.Put(uint32(cap(b)), b)
}

// singleConn represents a single connection to another Peer (IPFS Node).
type singleConn struct {
	local  peer.ID
	remote peer.ID
	maconn manet.Conn
	event  io.Closer
}

// newConn constructs a new connection
func newSingleConn(ctx context.Context, local, remote peer.ID, maconn manet.Conn) (Conn, error) {
	ml := lgbl.Dial("conn", local, remote, maconn.LocalMultiaddr(), maconn.RemoteMultiaddr())

	conn := &singleConn{
		local:  local,
		remote: remote,
		maconn: maconn,
		event:  log.EventBegin(ctx, "connLifetime", ml),
	}

	log.Debugf("newSingleConn %p: %v to %v", conn, local, remote)
	return conn, nil
}

// close is the internal close function, called by ContextCloser.Close
func (c *singleConn) Close() error {
	defer func() {
		if c.event != nil {
			c.event.Close()
			c.event = nil
		}
	}()

	// close underlying connection
	return c.maconn.Close()
}

// ID is an identifier unique to this connection.
func (c *singleConn) ID() string {
	return ID(c)
}

func (c *singleConn) String() string {
	return String(c, "singleConn")
}

func (c *singleConn) LocalAddr() net.Addr {
	return c.maconn.LocalAddr()
}

func (c *singleConn) RemoteAddr() net.Addr {
	return c.maconn.RemoteAddr()
}

func (c *singleConn) LocalPrivateKey() ic.PrivKey {
	return nil
}

func (c *singleConn) RemotePublicKey() ic.PubKey {
	return nil
}

func (c *singleConn) SetDeadline(t time.Time) error {
	return c.maconn.SetDeadline(t)
}
func (c *singleConn) SetReadDeadline(t time.Time) error {
	return c.maconn.SetReadDeadline(t)
}

func (c *singleConn) SetWriteDeadline(t time.Time) error {
	return c.maconn.SetWriteDeadline(t)
}

// LocalMultiaddr is the Multiaddr on this side
func (c *singleConn) LocalMultiaddr() ma.Multiaddr {
	return c.maconn.LocalMultiaddr()
}

// RemoteMultiaddr is the Multiaddr on the remote side
func (c *singleConn) RemoteMultiaddr() ma.Multiaddr {
	return c.maconn.RemoteMultiaddr()
}

// LocalPeer is the Peer on this side
func (c *singleConn) LocalPeer() peer.ID {
	return c.local
}

// RemotePeer is the Peer on the remote side
func (c *singleConn) RemotePeer() peer.ID {
	return c.remote
}

// Read reads data, net.Conn style
func (c *singleConn) Read(buf []byte) (int, error) {
	return c.maconn.Read(buf)
}

// Write writes data, net.Conn style
func (c *singleConn) Write(buf []byte) (int, error) {
	return c.maconn.Write(buf)
}

// ID returns the ID of a given Conn.
func ID(c Conn) string {
	l := fmt.Sprintf("%s/%s", c.LocalMultiaddr(), c.LocalPeer().Pretty())
	r := fmt.Sprintf("%s/%s", c.RemoteMultiaddr(), c.RemotePeer().Pretty())
	lh := u.Hash([]byte(l))
	rh := u.Hash([]byte(r))
	ch := u.XOR(lh, rh)
	return peer.ID(ch).Pretty()
}

// String returns the user-friendly String representation of a conn
func String(c Conn, typ string) string {
	return fmt.Sprintf("%s (%s) <-- %s %p --> (%s) %s",
		c.LocalPeer(), c.LocalMultiaddr(), typ, c, c.RemoteMultiaddr(), c.RemotePeer())
}
